Orthogonal Frequency Division Multiple Access (OFDMA) is a standard of a wireless communications system such as a cellular network system or a Wi-Fi system. An OFDMA system is to divide a transmission bandwidth into a series of subcarrier sets that are orthogonal and not overlapped, and allocate different subcarrier sets to different users, so as to implement multiple access.
With development and application of the Internet and wide popularization of portable sites such as smart phones, a higher requirement is made on channels of future data communication. In a highly dense application scenario, the current wireless local area network standard, namely, the IEEE802.11ac standard, cannot satisfy a requirement of a user on a data transmission rate. For a problem of the highly dense application scenario, a UL OFDMA (Up-Link Orthogonal Frequency Division Multiple Access) mechanism is first introduced in a wireless communications system, to increase a quantity of users for which transmission can be performed on a bandwidth simultaneously. However, after the UL OFDMA mechanism is introduced, a protocol of the wireless communications standard IEEE802.11ac is greatly changed. Therefore, a pilot structure of an existing spectrum and an allocation solution for a subcarrier need to be redesigned. Using a 20-MHz bandwidth as an example, the following problems of subcarrier allocation and pilot allocation need to be resolved. The problems are, for example, how many data subcarriers need to be allocated to one resource block (RB), how to set a pilot structure of each RB, how many users can be simultaneously connected on a bandwidth, and how to allocate resource blocks for each user.